EZH2 mediates lidamycin-induced cellular senescence through regulating p21 expression in human colon cancer cells.

Lidamycin (LDM) is a novel member of the enediyne antibiotics identified in China with potent antitumor activity. However, it remains unclear whether LDM has potential molecular targets that may affect its antitumor activity. Enhancer of zeste homolog 2 (EZH2) functions as a histone lysine methyltransferase and mediates trimethylation on histone 3 lysine 27 (H3K27me3). High EZH2 level is found to be positively correlated with the aggressiveness, metastasis and poor prognosis of cancer. Here, we aim to study the role of EZH2 in LDM-induced senescence, as well as in the cytotoxicity of LDM in human colon cancer cells. LDM is found to be relatively more potent in inhibiting the colon cancer cells harboring high EZH2 level and induces irreversible cellular senescence at IC50 dose range, as evidenced by senescence-associated ß-galactosidase staining, cell cycle arrest and molecular changes of senescence regulators including p21 in HCT116 and SW620 cells. More importantly, LDM is found to markedly inhibit EZH2 expression at both protein and mRNA levels upon the induction of p21 and cellular senescence. LDM also selectively inhibits EZH2 expression as compared with other histone lysine methyltransferases. Knockdown of p21 with siRNAs abolishes LDM-induced senescence, whereas EZH2 knockdown markedly increases p21 expression and causes senescent phenotype. Enrichment of both EZH2 and H3K27me3 levels in the p21 promoter region is reduced by LDM. Moreover, EZH2 overexpression reduces cellular senescence, p21 expression and DNA damage response upon LDM exposure. LDM also demonstrates potent antitumor efficacy in xenografted animal models. Collectively, our work provides first demonstration that EZH2 may mediate, at least partially, the senescence-inducing effects of LDM by regulating p21 expression and DNA damage effect. Thus, EZH2 may serve as a potential target and biomarker to indicate the clinical efficacy of the potent enediyne antitumor drug.

Overexpression of gelsolin reduces the proliferation and invasion of colon carcinoma cells.

The enhanced motility of cancer cells via the remodeling of the actin cytoskeleton is crucial in the process of cancer cell invasion and metastasis. It was previously demonstrated that gelsolin (GSN) may be involved as a tumor or a metastasis suppressor, depending on the cell lines and model systems used. In the present study, the effect of GSN on the growth and invasion of human colon carcinoma (CC) cells was investigated using reverse transcription quantitative polymerase chain reaction and western blotting. It was observed that upregulation of the expression of GSN in human CC cells significantly reduced the invasiveness of these cells. The expression levels of GSN were observed to be reduced in CC cells, and the reduced expression level of GSN was often associated with a poorer metastasis­free survival rate in patients with CC (P=0.04). In addition, the overexpression of GSN inhibited the invasion of CC cells in vitro. Furthermore, GSN was observed to inhibit signal transducer and activator of transcription (STAT) 3 signaling in CC cells. Together, these results suggested that GSN is critical in regulating cytoskeletal events and inhibits the invasive and/or metastatic potential of CC cells. The results obtained in the present study may improve understanding of the functional and mechanistic links between GSN as a possible tumor suppressor and the STAT3 signaling pathway, with respect to the aggressive nature of CC. In addition, the present study demonstrated the importance of GSN in regulating the invasion and metastasis of CC cells at the molecular level, suggesting that GSN may be a potential predictor of prognosis and treatment success in CC.

Early activated hepatic stellate cell-derived molecules reverse acute hepatic injury.

AIM: To test whether hepatic stellate cells (HSCs) at different activation stages play different roles in acetaminophen (APAP)-induced acute liver injury (ALI). METHODS: HSCs were isolated from mouse liver and cultured in vitro. Morphological changes of initiation HSCs [HSCs (5d)] and perpetuation HSCs [HSCs (p3)] were observed by immunofluorescence and transmission electron microscopy. The protective effects of HSC-derived molecules, cell lysates and HSC-conditioned medium (HSC-CM) were tested in vivo by survival and histopathological analyses. Liver injury was determined by measuring aminotransferase levels in the serum and by histologic examination of tissue sections under a light microscope. Additionally, to determine the molecular mediators of the observed protective effects of initiation HSCs, we examined HSC-CM using a high-density protein array. RESULTS: HSCs (5d) and HSCs (p3) had different morphological and phenotypic traits. HSCs (5d) presented a star-shaped appearance with expressing α-SMA at non-uniform levels between cells. However, HSCs (p3) evolved into myofibroblast-like cells without lipid droplets and expressed a uniform and higher level of α-SMA. HSC-CM (5d), but not HSC-CM (p3), provided a significant survival benefit and showed a dramatic reduction of hepatocellular necrosis and panlobular leukocyte infiltrates in mice exposed to APAP. However, this protective effect was abrogated at higher cell masses, indicating a therapeutic window of effectiveness. Furthermore, the protein array screen revealed that HSC-CM (5d) was composed of many chemokines and growth factors that correlated with inflammatory inhibition and therapeutic activity. When compared with HSC-CM (p3), higher levels of monocyte chemoattractant protein-1, macrophage inflammatory protein-1γ, hepatocyte growth factor, interleukin-10, and matrix metalloproteinase-2, but lower levels of stem cell factor and Fas-Ligand were observed in HSC-CM (5d). CONCLUSION: These data indicated that initiation HSCs and perpetuation HSCs were different in morphology and protein expression, and provided the first experimental evidence of the potential medical value of initiation HSC-derived molecules in the treatment of ALI.

Primary colonic melanoma presenting as ileocecal intussusception: case report and literature review.

Primary malignant melanoma originating in the colon is an extremely rare disease. Herein, we report a case of primary melanoma of the ascending colon. The patient was a 57-year-old male who was admitted to our hospital for persistent abdominal pain and episodes of bloody stool, nausea and vomiting. A computed tomography scan revealed lower intestinal intussusception and enlarged lymph nodes in the abdominal cavity and retroperitoneum. During laparoscopic operation, multiple enlarged lymph nodes were found. Several segments of the proximal small intestine were incarcerated into the distal small intestine, forming an internal hernia and obstruction. The necrotic terminal ileum was invaginated into the ascending cecum. Subsequently, adhesive internal hernia reduction and palliative right hemicolectomy were performed. Pathologic examination of the excised specimen revealed a polypoid mass in the ascending colon. Histological examination showed epithelioid and spindle tumor cells with obvious cytoplasmic melanin deposition. Immunohistochemical staining revealed that the tumor cells were positive for S-100, HMB-45 and vimentin, confirming the diagnosis of melanoma. The patient history and a thorough postoperative investigation excluded the preexistence or coexistence of a primary lesion elsewhere in the skin, anus or oculus or at other sites. Thus, we consider our case to represent an aggressive primary colon melanoma presenting as ileocecal intussusception and intestinal obstruction.

[Application of enhanced recovery program after surgery(ERAS) in patients undergoing radical resection for colorectal cancer].

OBJECTIVE: To compare the enhanced recovery program after surgery (ERAS) with conventional perioperative management in patients undergoing radical resection for colorectal cancer. METHODS: The ERAS protocol included a combination of evidence-based and consensus methodology. A total of 597 consecutive patients undergoing elective colorectal resection were randomized to either the ERAS(n=299) or the control group(n=298). Outcomes related to nutrition and metabolism index, stress index, and recovery index were measured and recorded. RESULTS: Demographics and operative parameters were similar between the two groups(P>0.05). The nutritional status of patients in the ERAS group was improved after surgery compared with that of the control group. On postoperative day (POD) 1, the HOMA-IR in the ERAS group was significantly lower than that in the control group(P<0.01). The cortisol level in the control group was elevated on both POD 1(P<0.01) and POD 5(P<0.01) compared to the preoperative level. However, the cortisol level was not increased until POD 5(P<0.01) in the ERAS group. The levels of TNF-α, IL-1ß, IL-6, and IFN-γ were reduced in the ERAS group, indicating less postoperative stress responses compared with the control group. In addition, ERAS group was associated with accelerated recovery of gastrointestinal function. The postoperative length of stay [(5.7±1.6) d vs. (6.6±2.4) d, P<0.01] and expense[(15 998±2655) RMB vs. (17 763±3059) RMB, P<0.01] were reduced in the ERAS group. Twenty-eight patients(9.4%) in the control group and 29(9.7%) in the ERAS group developed complications, while the difference was not statistically significant(P>0.05). CONCLUSION: ERAS protocol alleviates surgical stress response and accelerates postoperative recovery without compromising patient safety.

XbaI polymorphisms of apolipoprotein B gene: another risk factor of gallstone formation after radical gastrectomy.

AIM: To prospectively investigate the association between the XbaI polymorphisms of apolipoprotein B (APOB) gene and gallstone formation following gastrectomy. METHODS: The study was conducted between January 2005 and December 2006. A total of 186 gastric cancer patients who had undergone radical gastrectomy were grouped according to XbaI polymorphisms of APOB gene (X(+)X(-) group, n = 24 and X(-)X(-) group, n = 162) and compared. The XbaI polymorphisms of APOB gene were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: The incidence of gallstone was significantly higher in the X(+)X(-) group than in the X(-)X(-) group [54.2% vs 9.3%, RR = 5.85 (2.23-15.32), P < 0.001]. The serum levels of total cholesterol (TC) and low-density lipoprotein (LDL) were higher in the X(+)X(-) than in the X(-)X(-) group (4.02 +/- 1.12 vs 3.48 +/- 0.88, P = 0.004 before surgery and 3.88 +/- 1.09 vs 3.40 +/- 0.86, P = 0.008 after surgery). LDL was 2.21 +/- 0.96 vs 1.89 +/- 0.84 (P = 0.042) before surgery and 2.09 +/- 0.95 vs 1.72 +/- 0.85 (P = 0.029) after surgery in the two groups. No relationship was found between XbaI polymorphisms and gallbladder motility. CONCLUSION: In Chinese patients after radical gastrectomy, X(+) allele of APOB gene is another risk factor for the development of gallstone besides the gallbladder motility disorder after surgery.

[Relationship of gallstone formation after radical gastrectomy with the polymorphisms of apolipoprotein B Xba I and lipoprotein lipase Hind III gene].

OBJECTIVE: To investigate the relationship of gallstone formation after radical gastrectomy with the polymorphisms of apolipoprotein B (ApoB) Xba I gene and lipoprotein lipase (LPL) Hind III gene. METHODS: A total of 80 gastric cancer patients who underwent radical gastrectomy at our hospital between January 2006 and December 2006 were divided into different groups according to the polymorphisms of ApoB Xba I gene and LPL Hind III gene. The gene polymorphism was detected by polymerase chain reaction-restriction fragment length polymorphism. Gallstone formation 2 years after radical gastrectomy was compared among different genotype groups. RESULTS: Eight patients were lost to follow-up. According to the genotype detection, 72 patients were divided into X(+)X(-) group (10 cases), X(-)X(-) group (62 cases), H(-) group (27 cases) and H(-) deletion group (45 cases). The incidence of gallstone was significantly higher in X(+)X(-) group than that in X(-)X(-) group (60.0% vs 6.5%, P<0.01). The serum levels of total cholesterol TC and low density lipoprotein were significantly higher in X(+)X(-) group than those in X(-)X(-) group (P<0.05), but the level of ApoB was not significantly different between the two groups. The incidence of gallstone was not significantly different between H(-) group and H(-) deletion group (14.8% vs 13.3%). The level of triglyceride in H(-) group was significantly lower than that in H(-) deletion group before operation, however the difference disappeared after operation. CONCLUSION: X(+) allele may be associated with gallstone formation after radical gastrectomy, while H(-) may not.

[Cellular immunity induced by CD40 ligand-activated dendritic cells in CEA transgenic mice].

OBJECTIVE: To investigate the role of CD40 ligand (CD40L) in dendritic cells (DC) of CEA transgenic mice and to evaluate the specific cellular immunity induced by activated DC. METHODS: Bone marrow cells of the CEA transgenic mice were used to generate immature dendritic cells under the condition of GM-CSF and IL-4. CD40L was added to activate dendritic cells into mature phenotype. Dendritic cells cancer vaccine was pulsed with CEA526-533 peptide which made the vaccine specific for cancer immunity. The immunophenotype molecules were identified by flow cytometry. The cytokines produced by cells were determined by ELISA. T cells proliferation was measured by (3)H-thymidine essays. RESULTS: Immunophenotype molecules expressions of CD40L-activated dendritic cells were significantly higher than those in control group. IL-12 secretion by CD40L-activated dendritic cells was (937.81+/-51.99) pg/10(6) DC, significantly higher than that in control group [(83.06+/-8.58) pg/10(6) DC, P<0.01]. CD8(+) T cells proliferation induced by CD40 L-activated dendritic cells was stronger as compared to control group (P<0.05), and the secretion of IFN-gamma was(33.900+/-4.550) ng/L, significantly higher than that in control group [(5.226+/-0.460) ng/L, P<0.01]. Splenocytes proliferation induced by CD40 L-activated dendritic cells was stronger as compared to control group (P<0.01), and the secretion of IFN-gamma was (69.802+/-11.407) ng/L, significantly higher than that in control group [(2.912+/-0.562) ng/L, P<0.01]. CONCLUSION: The method of using CD40L to stimulate bone marrow-delivered dendritic cells promotes the maturation and activation of dendritic cells, which enhances the cellular immunity in CEA transgenic mice.

[Establish predictive model of colorectal cancer by using surface enhanced laser desorption/ionization-time of flight-mass spectrometry].

OBJECTIVE: To establish serum proteome fingerprinting predictive models and search for proteins associated with colorectal cancer. METHODS: Thirty-six randomly selected colorectal cancer patients and 36 cases with hernia or gall bladder diseases scheduled for elective operation were enrolled as cancer group and control group respectively. Peripheral venous blood samples were collected before the operations. Special serum protein or peptide fingerprint was investigated by using surface enhanced laser desorption/ ionization-time of flight-mass spectrometry (SELDI-TOF-MS) measurement after blood sample had been treated with weak cation exchange protein chip (CM10) for each case. The obtained data were analyzed by Biomarker Wizard software to screen serum proteome tumor markers and set up diagnosis predictive model for colorectal cancer. Blind validation of the model with 44 healthy controls and 88 colorectal cancer patients were carried out by using Biomarker Patterns Software. RESULTS: In comparing colorectal cancer group with control group, 5 specific protein peaks (P < 0.05) were found. The predictive model had a sensitivity of 100% and a specificity of 97.2%. A sensitivity of 71.6% and a specificity of 72.7% was got with the blind validation. The specific protein peaks with a mass-to-charge ratio (m/z) of 8908 and 13,707 showed in all the results and it showed their strong relationship with colorectal cancer. CONCLUSIONS: The predictive models built by the differences of serum proteome fingerprint could be a very useful diagnostic tool in colorectal cancer. Proteins with m/z of 8908 and 13,707 would possibly be the tumor markers of colorectal cancer.

[Evaluation of the preoperative staging of rectal cancer by magnetic resonance imaging].

OBJECTIVE: To evaluate the value of MRI in preoperative staging of rectal cancer. METHODS: The data of 156 rectal cancer patients,undergone MRI scans from December 2004 to June 2006 in our hospital, were analyzed retrospectively. Findings of MRI were compared with postoperative pathological examinations. RESULTS: Intracavitary localized parenchyma tumors were seen in 72 cases, and intestinal wall abnormal incrassation or stricture in other 84 cases from MRI scan. Sixteen cases had rectal polyps simultaneously, 2 cases ovarian cysts, 13 cases anterior-sacral metastases and 2 cases bone metastases. The sensitivity and specificity of T(1-2), T(3) and T(4) rectal cancer by MRI examination were 25%(8/32), 93.3%(84/90), 94.1%(32/34) and 100%(124/124), 57.6%(38/66), 96.7%(118/122) respectively. In MRI imaging, metastatic para-rectal lymph node was diagnosed as the diameter >5 mm or abnormal border or mixed resonance, with a sensitivity of 85.1%(80/94) and specificity of 45.2%(28/62). CONCLUSION: MRI has high accuracy for preoperative staging of rectal cancer, and is useful to detect the serosal infiltration and lymph node metastasis.

[Application of SELDI-TOF-MS in detection of liver metastasis from colorectal cancer].

OBJECTIVE: To establish a serum protein fingerprint model for prediction of liver metastasis from colorectal cancer by SELDI-TOF-MS analysis, and to determine the differentiatial proteins associated with the metastatic liver cancers. METHODS: Data were collected from the Department of General Surgery in Zhongshan Hospital. A group of patients with colorectal cancer (CRC) without liver metastasis (n = 36) and another group with liver metastasis (n = 36) were included in this study. Serum samples were collected from peripheral venous blood before operation. Special serum protein or peptide fingerprint was determined by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). The obtained data were analyzed by Biomarker Wizard software to screen the serum protein markers discriminating colorectal cancer patients with and without liver metastasis. A serum protein fingerprint model was established. This model was blindly verified in of CRC patients with and 44 cases without liver metastasis. RESULTS: Comparing the characteristic proteins in those two groups of patients, 10 specific protein peaks were identified with statistical significance (P < 0.05). According to m/z growing from small to large, they were: 2398, 2814, 4084, 4289, 4465, 6422, 6619, 11 482, 11 649 and 13 714. The predictive model had a sensitivity of 91.7% and a specificity of 97.2%. The validation showed a sensitivity of 75.0% and a specificity of 81.8%. CONCLUSION: A predictive model based on differentiatial serum protein fingerprint with high sensitivity and specificity has been successfully established. It should be a very useful tool in detection and diagnosis of liver metastasis in colorectal cancer patients.

[Therapeutic effects of hepatic resection in liver metastasis of colorectal cancer].

OBJECTIVES: To evaluate therapeutic effects of hepatic resection in liver metastasis of colorectal cancer (LMCC). METHODS: The clinical data of 133 cases of LMCC received hepatic resection from January 1, 2000 to December 31, 2005 in Zhongshan Hospital were analyzed retrospectively. The relationship between hepatic resection and survival rate was also concerned. RESULTS: One hundred and thirty-three cases received curative hepatic resection in all 470 LMCC cases, of which 30 cases from synchronous liver metastasis (SLM) group (totaled 196 cases) and 103 cases from metachronous liver metastasis (MLM) group (totaled 274 cases). Mortality rate during operation was 3.3% in SLM and 1.9% in MLM (P < 0.05). All patients were followed-up till June 31, 2006, the 1, 3, 5 year survival rates and median survival time of SLM were similar to those of MLM, but its recurrence rate was higher (36.7% vs 20.4%, P = 0.030). The 1, 3, 5 year survival rate in the 49 patients who were operable but received non-operation treatment were significantly lower than those in operated patients (P = 0.003). In 30 SLM cases, 22 received I stage resection of their primary and liver metastasis tumor and 8 received liver metastasis resection after the primary surgery (II stage operation), 1, 2, 3 year survival and the median survival time were similar in the two groups. With COX multivariate analysis, incision margin > or = 1 cm (P = 0.036) and reoperation after recurrence (P = 0.041) were protective survival factors, and post-operation recurrence (P = 0.023) was survival risk factor. CONCLUSIONS: Curative hepatic resection is the first choice of therapy in liver metastasis of colorectal cancer and it can improve survival.

Effects and probable mechanisms of electroacupuncture at the Zusanli point on upper gastrointestinal motility in rabbits.

BACKGROUND AND AIM: The purposes of this study were to investigate the regulative effect of acupuncture on gastrointestinal motility in rabbits and to explore the probable mechanism of electroacupuncture. METHODS: The experiment was performed on 30 rabbits implanted with three pairs of electrodes, which were equally divided into three groups: the control group, the Zusanli group, and the non-acupuncture point group. The gastrointestinal myoelectrical activity of each conscious rabbit was recorded when acupuncture was applied. Motilin in plasma, cholecystokinin (CCK) in serum, the activity of acetylcholine esterase, nitric oxide synthase (NOS), and the vesicle of nerve endings in the stomach tissue and jejunum were investigated. RESULTS: It was found that electroacupuncture did not exert much influence on the slow wave of gastrointestinal myoelectrical activity, but significantly increased the number and amplitude of spikes. In the Zusanli group, the concentration of motilin and CCK was much higher at the post-acupuncture stage than at the pre-acupuncture stage. Electroacupuncture significantly enhanced the activity of acetylcholine esterase. Moreover, we found out that in the Zusanli group, the number of vesicles without granula was significantly fewer than in the control group. The activity of NOS was less in the Zusanli group than in the control group. CONCLUSIONS: Acupuncture may enhance the gastrointestinal myoelectrical activity of conscious rabbits. The cholinergic nerve, nitric oxide, motilin, and CCK may contribute to acupuncture mechanisms.

[Application of the protocol of enhanced recovery after surgery in colorectal surgery].

OBJECTIVE: To evaluate enhanced recovery after surgery(ERAS) protocol in colorectal surgery. METHODS: From september 2006 to February 2007, 74 patients with colorectal cancer were randomly assigned to ERAS group and control group. The stress index, nutrition and metabolism index, intraoperative index and postoperative index were evaluated. RESULTS: Six patients were excluded, 3 in ERAS group (2 cases received hepatectomy concomitantly and 1 case received partial ileum resection), and 3 in control group (1 case received hepatectomy and 1 case received colorectomy concomitantly, another presented asthma paroxysm). So there were 34 cases in ERAS group and 34 cases in control, with no statistical differences in sex, age, BMI index and operation types. Deviation of HOMA-IR index of ERAS was lower than the control (P>0.05), the same as plasma cortisol at the 1st day after operation (P<0.05), but plasma glucagons in the operation of ERAS group was higher than that of control (P<0.05). Plasma glucose 1st day after operation of ERAS group was lower than control (P<0.05), while plasma triglyceride intraoperation, at 1st day, 2nd day after operation of ERAS was higher than control (P<0.05). Nitrogen negative balance of ERAS group was higher than control at 2nd day after surgery, but is lower intraoperation and at 6th day after operation (P<0.05). The time of exhaust gas and stool, time to eat fluidity and semi-fluidity, out-of-bed time and exercise time per-day, residual time and complication rate in ERAS group were better than those of control (P<0.05). Post-operative expenses of ERAS was lower than that of control (P<0.05). CONCLUSION: ERAS can decrease surgical stress, increase functional recovery and reduce complication rate.

[Preoperative hepatic and regional arterial infusion chemotherapy in the prevention of liver metastasis after colorectal cancer surgery].

OBJECTIVE: To investigate the effects of preoperative hepatic and regional arterial infusion chemotherapy (PHRAIC) in the prevention of liver metastasis of colorectal cancer after surgery. METHODS: 110 patients of colorectal cancer underwent perfusion of 3 anti-tumor drugs into the hepatic artery and nutrient artery of the tumor respectively, radical surgery of the colorectal cancer 7 days after, and then general venous chemotherapy 3 weeks after operation, 112 patients underwent radical surgery of the colorectal cancer and general venous chemotherapy 3 weeks after operation. Follow-up was carried out every month with a follow-up period of 34 months +/- 3 months. RESULTS: There were no significant difference in post-operational complications between these 2 groups. The 3-year liver metastasis rate, 3-year tumor-free survival rate, overall survival rate, and median survival time of the stage III patients in the PHRAIC group were 12.7%, 82.3%, 87.7%, and 40 months +/- 5 months, all significantly better than those in the control group (28.3%, 58.7%, 75.5%, and 36 months +/- 3 months respectively, P < 0.05 or P < 0.01). CONCLUSION: PHRAIC reduces the liver metastasis of colorectal cancer after radical surgery and improves the survival of the stage III patients.

[In vitro evidence for pancreatic lineage: Ngn3 positive cells are endocrine progenitors derived from cultured islets].

OBJECTIVE: Further studies have been conducted to evaluate the roles of Ngn3 in adult islet maintenance and renewal. METHODS: Islets were isolated from 6 - 8 week old male C57BL/6 mice. After common bile duct cannulation, the pancreas was resected and digested in collagenase V (2.5 mg/ml). Islets were then handpicked and 10 - 12 islets were plated in 60 mm culture dish and cultivated with RPMI-1640, which contained 12.5 mmol/L HEPES, 5.2 mmol/L glucose and 2% fetal bovine serum (FBS). Islet cells were analyzed by immunocytochemistry methods for A6, insulin, glucagon, nestin, Ngn3 and 5-bromo-2'-deoxy-uridine (BrdU). RESULTS: The results of these studies indicated that less than 15 percent of proliferated islet cells were Ngn3 expressing cells, in which about one third of the Ngn3 positive cells co-expressed A6. The existence of Ngn3 in cultured islet cells is consistent with the results from other's findings both in embryogenesis and adult islet studies. A significant finding of our study is that the existence of A6 and Ngn3 co-expressing cells in the cultured islet. A6 is a marker for identifying bile duct epithelial cell oriented hepatic progenitor cells. Islet-derived A6 cells are possibly born in the adult pancreatic duct and migrate into islets. A6 cells co-express Ngn3 when these cells commit to endocrine lineage within the islets. More interestingly, islet-derived A6 positive cells have the potential to transdifferentiate into hepatic cells. CONCLUSION: The presence of Ngn3(+) and A6(+) cells in the cultured islets suggests that the four established islet cell types arise from a common endocrine lineage residing within the adult islets. A6 and Ngn3 are useful markers for understanding intra-islet adult stem cell lineages in our future studies. This approach may allow for significant advances in understanding the IPC proliferation and differentiation, and open the possibility of using intra-islet adult stem cells for diabetes treatment.